When someone suffers a stroke, 1.9 million nerve cells in the
brain die each minute, and the oxygen-starved brain ages about
3.6 years each hour -- further emphasizing the need for rapid
treatment -- researchers say.

"'Time is brain' is a popular saying: clinical outcomes have
been shown to deteriorate the longer treatment is delayed," study
author Dr. Jeffrey L. Saver, from the University of California
in Los Angeles stated.

However, he added, until recently the technology did not exist
to precisely count the number of neurons lost with each passing
minute that the blood supply is interrupted to the affected region.

Advances in stroke neuroimaging coupled with data from previous
research have allowed Saver to estimate the neuron loss that
occurs during a typical stroke.

The average stroke involves 54 milliliters of brain tissue --
about 3 cubic inches -- and takes 10 hours to evolve, the investigator
reports in the American Heart Association's journal Stroke.

As noted, each minute a stroke ticks by untreated, 1.9 million
neurons die, resulting in the loss of 14 billion synapses (nerve
junctions) and 7.5 miles of nerve fibers. According to the report,
the forebrain, the most common site of strokes, contains a total
of 22 billion neurons, on average.

"I was simultaneously not surprised by the findings, but astounded
by the magnitude," Saver said. "From caring for patients whose
lives are forever altered by crippling stroke, I knew intuitively
that stroke is a devastating disease that evolves rapidly. On
the other hand, seeing the raw numbers of exactly how much damage
occurs astounds me."

The findings drive home the message that "patients need to recognize
stroke symptoms and call 911 right away. ER physicians, neurologists,
and nurses need to recognize that stroke is a treatable neuro
emergency that has to be handled at the highest triage priority."